From patchwork Thu Feb  8 13:43:37 2018
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Subject: [3/4] clk: bcm2835: De-assert/assert PLL reset signal when appropriate
From: Boris Brezillon <boris.brezillon@bootlin.com>
X-Patchwork-Id: 10207157
Message-Id: <20180208134338.24590-3-boris.brezillon@bootlin.com>
To: Florian Fainelli <f.fainelli@gmail.com>, Ray Jui <rjui@broadcom.com>,
 Scott Branden <sbranden@broadcom.com>,
 bcm-kernel-feedback-list@broadcom.com,
 Stephen Warren <swarren@wwwdotorg.org>,
 Lee Jones <lee@kernel.org>, Eric Anholt <eric@anholt.net>,
 linux-rpi-kernel@lists.infradead.org,
 Mike Turquette <mturquette@baylibre.com>,
 Stephen Boyd <sboyd@codeaurora.org>, linux-clk@vger.kernel.org
Cc: Boris Brezillon <boris.brezillon@bootlin.com>, stable@vger.kernel.org
Date: Thu,  8 Feb 2018 14:43:37 +0100

In order to enable a PLL, not only the PLL has to be powered up and
locked, but you also have to de-assert the reset signal. The last part
was missing. Add it so PLLs that were not enabled by the FW/bootloader
can be enabled from Linux.

Fixes: 41691b8862e2 ("clk: bcm2835: Add support for programming the audio domain clocks")
Cc: <stable@vger.kernel.org>
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
---
 drivers/clk/bcm/clk-bcm2835.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/clk/bcm/clk-bcm2835.c b/drivers/clk/bcm/clk-bcm2835.c
index a07f6451694a..6c5d4a8e426c 100644
--- a/drivers/clk/bcm/clk-bcm2835.c
+++ b/drivers/clk/bcm/clk-bcm2835.c
@@ -602,6 +602,9 @@ static void bcm2835_pll_off(struct clk_hw *hw)
 	const struct bcm2835_pll_data *data = pll->data;
 
 	spin_lock(&cprman->regs_lock);
+	cprman_write(cprman, data->a2w_ctrl_reg,
+		     cprman_read(cprman, data->a2w_ctrl_reg) &
+		     ~A2W_PLL_CTRL_PRST_DISABLE);
 	cprman_write(cprman, data->cm_ctrl_reg,
 		     cprman_read(cprman, data->cm_ctrl_reg) |
 		     CM_PLL_ANARST);
@@ -640,6 +643,10 @@ static int bcm2835_pll_on(struct clk_hw *hw)
 		cpu_relax();
 	}
 
+	cprman_write(cprman, data->a2w_ctrl_reg,
+		     cprman_read(cprman, data->a2w_ctrl_reg) |
+		     A2W_PLL_CTRL_PRST_DISABLE);
+
 	return 0;
 }