misc: atmel_tclib: get and use slow clock
authorBoris Brezillon <boris.brezillon@free-electrons.com>
Sun, 16 Aug 2015 09:23:46 +0000 (11:23 +0200)
committerAlexandre Belloni <alexandre.belloni@free-electrons.com>
Tue, 6 Oct 2015 10:33:14 +0000 (12:33 +0200)
Commit dca1a4b5ff6e ("clk: at91: keep slow clk enabled to prevent system
hang") added a workaround for the slow clock as it is not properly handled
by its users.

Get and use the slow clock as it is necessary for the timer counters.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Thierry Reding <thierry.reding@gmail.com>
drivers/clocksource/tcb_clksrc.c
drivers/misc/atmel_tclib.c
drivers/pwm/pwm-atmel-tcb.c
include/linux/atmel_tc.h

index f8d11fc..6ee9140 100644 (file)
@@ -193,10 +193,17 @@ static int __init setup_clkevents(struct atmel_tc *tc, int clk32k_divisor_idx)
        struct clk *t2_clk = tc->clk[2];
        int irq = tc->irq[2];
 
+       ret = clk_prepare_enable(tc->slow_clk);
+       if (ret)
+               return ret;
+
        /* try to enable t2 clk to avoid future errors in mode change */
        ret = clk_prepare_enable(t2_clk);
-       if (ret)
+       if (ret) {
+               clk_disable_unprepare(tc->slow_clk);
                return ret;
+       }
+
        clk_disable(t2_clk);
 
        clkevt.regs = tc->regs;
@@ -209,6 +216,7 @@ static int __init setup_clkevents(struct atmel_tc *tc, int clk32k_divisor_idx)
        ret = request_irq(irq, ch2_irq, IRQF_TIMER, "tc_clkevt", &clkevt);
        if (ret) {
                clk_unprepare(t2_clk);
+               clk_disable_unprepare(tc->slow_clk);
                return ret;
        }
 
index 0ca05c3..ac24a4b 100644 (file)
@@ -125,6 +125,10 @@ static int __init tc_probe(struct platform_device *pdev)
        if (IS_ERR(clk))
                return PTR_ERR(clk);
 
+       tc->slow_clk = devm_clk_get(&pdev->dev, "slow_clk");
+       if (IS_ERR(tc->slow_clk))
+               return PTR_ERR(tc->slow_clk);
+
        r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        tc->regs = devm_ioremap_resource(&pdev->dev, r);
        if (IS_ERR(tc->regs))
index 6da01b3..75db585 100644 (file)
@@ -305,7 +305,7 @@ static int atmel_tcb_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
         */
        if (i == 5) {
                i = slowclk;
-               rate = 32768;
+               rate = clk_get_rate(tc->slow_clk);
                min = div_u64(NSEC_PER_SEC, rate);
                max = min << tc->tcb_config->counter_width;
 
@@ -387,9 +387,9 @@ static int atmel_tcb_pwm_probe(struct platform_device *pdev)
 
        tcbpwm = devm_kzalloc(&pdev->dev, sizeof(*tcbpwm), GFP_KERNEL);
        if (tcbpwm == NULL) {
-               atmel_tc_free(tc);
+               err = -ENOMEM;
                dev_err(&pdev->dev, "failed to allocate memory\n");
-               return -ENOMEM;
+               goto err_free_tc;
        }
 
        tcbpwm->chip.dev = &pdev->dev;
@@ -400,17 +400,27 @@ static int atmel_tcb_pwm_probe(struct platform_device *pdev)
        tcbpwm->chip.npwm = NPWM;
        tcbpwm->tc = tc;
 
+       err = clk_prepare_enable(tc->slow_clk);
+       if (err)
+               goto err_free_tc;
+
        spin_lock_init(&tcbpwm->lock);
 
        err = pwmchip_add(&tcbpwm->chip);
-       if (err < 0) {
-               atmel_tc_free(tc);
-               return err;
-       }
+       if (err < 0)
+               goto err_disable_clk;
 
        platform_set_drvdata(pdev, tcbpwm);
 
        return 0;
+
+err_disable_clk:
+       clk_disable_unprepare(tcbpwm->tc->slow_clk);
+
+err_free_tc:
+       atmel_tc_free(tc);
+
+       return err;
 }
 
 static int atmel_tcb_pwm_remove(struct platform_device *pdev)
@@ -418,6 +428,8 @@ static int atmel_tcb_pwm_remove(struct platform_device *pdev)
        struct atmel_tcb_pwm_chip *tcbpwm = platform_get_drvdata(pdev);
        int err;
 
+       clk_disable_unprepare(tcbpwm->tc->slow_clk);
+
        err = pwmchip_remove(&tcbpwm->chip);
        if (err < 0)
                return err;
index b87c1c7..468fdfa 100644 (file)
@@ -67,6 +67,7 @@ struct atmel_tc {
        const struct atmel_tcb_config *tcb_config;
        int                     irq[3];
        struct clk              *clk[3];
+       struct clk              *slow_clk;
        struct list_head        node;
        bool                    allocated;
 };